How can I prevent a page from navigating away if a textbox is not filled?

[SuperJediMedia]

I have

 

<asp:TextBox ID="info" runat="server" CausesValidation="true" ValidateRequestMode="Enabled" />

 

// A textbox called info

 

<asp:RequiredFieldValidator ID="RequiredFieldValidator1" runat="server"

ControlToValidate="info" ErrorMessage="You must enter something" Display="Dynamic"> </asp:RequiredFieldValidator>

 

//A validator to make sure info is filled.

 

 

 

But, I am still able to navigate away from the page.

What else do I need?

 

 

Do I need to in every other <asp: controls type in some stuff as well? Or just only one more block of code will do it?

 

[SuperJediMedia]

Hey, please tell me what I need to do, please? What code would I need?

[Seahorsepip Veteran]

Seems to work fine in this w3schools demo: http://www.w3schools.com/aspnet/showaspx.asp?filename=demo_reqfieldvalidator

Check if you missed something compared to the demo.

[SuperJediMedia]

I need a code that prevent me from going to another link (within my site) when the textbox isn't entered.

 

That demos is very basic, just shows the simply error message and not on navigating away from the page.

 

I know how to display error messages, but the 'unable navigating away form the page' baffles me.
 

 

 

The validation control does not care about users navigating onto other pages, but I need to know how to do this.

 

[SuperJediMedia]

Let me clarify what I mean,

 

if textbox is empty, or a button that inputs the value from the textbox has not been clicked, you can not visit any other pages that's linked, that includes a masterpage and trees/menus

 

It need to stay on that page until this information is entered into the box.
 

Do you understand what I mean?
 

[Stoffel]

I guess you would have to have an event handler for clicking the links

can't you put some code in there that checks if the length of the field is not 0

if so then just do nothing, otherwise you move on

[SuperJediMedia]

What event-handler do I need? But Where does it go? Since everything is ALL combined with a masterpage, so it should go inside the Master page or just that page where you are required to enter a text?
 

Maybe it should go under Master page, I dunno. I also have ASP menus/trees, that can't function either unless this textbox MUST enter a value.

 

[TAZMINATOR]

  On 15/11/2014 at 21:29, SuperJediMedia said:

Let me clarify what I mean,

 

if textbox is empty, or a button that inputs the value from the textbox has not been clicked, you can not visit any other pages that's linked, that includes a masterpage and trees/menus

 

It need to stay on that page until this information is entered into the box.

 

Do you understand what I mean?

 

 

If you want to tell the users to fill the form and lock them on that page until the form is filled out, then that would be a problem...

 

because it doesn't work that way because the user can close the browser down and pull it up and visit somewhere else.

[SuperJediMedia]

  Quote

because it doesn't work that way because the user can close the browser down and pull it up and visit somewhere else.

 

I think I know what you are saying, but it's not what I mean at all

I am trying to learn how to program/design a website, understanding how THIS aspect work, everything within this site is what I need to worry about.  What you are talking about (The web browsing basics) isn't what I am talking about.

 

[SuperJediMedia]

I think whoever said I need an event-handler is absolutely right. I just need to know where & what to code to make it work.

[SuperJediMedia]

Correct me if I am wrong, but I believe I should put this event-handler inside the Master Page, not just this one page. Since if I goto  any of the other links, it can't access them unless I input something from this textbox into memory, first.

 

 

Like inside Master Page's

 

protected void Page_Load(object sender, EventArgs e)

 

{

 

I put in something to check the value of text.

}
 

Any tutorials on this would be great. I can't find them though :(

[SuperJediMedia]

Well I said in the Master Page Page_Load that

 

 if  (this text value == null)

 

{

 

Response.Redirect(" (to this page to input values into the text box)");

 

}

 

But it doesn't do that, it acts like this value isn't null, I am pretty sure that it is null though.

[SuperJediMedia]

Please, I really got to know how to do this. If any of you can even just share with me an online Tutorial that talks about how to prevent a page from navigating away, I would be greatly appreciated!!!

[Guest]

Hmm, can't you just add the required HTML tag to it? It has been a long time since I touched asp, so I might be wrong here.

[Seahorsepip Veteran]

Why not write some actual js instead of using asp...

Anyway theres a problem you will run into, you cannot and never will be able to prevent a user from navigating away. Most you can do is showing an alert popup.

What you can do is preventing a user from clicking a link on your page and navigating to the link url.

Following code can be used for that:

$("a").click(function(e) {

if($("#inputelement to check").val() == "") {

e.preventDefault();

}

};

Above code uses jquery but can also be written with pure js.

If you want to learn some proper web development I'd suggest to not depend on asp only but also learn js...

To make writing js simpler you can try learning jquery which is simple js library and easier to learn then pure js, especially when working with the dom.

Keep in mind that this is bypassable for users with disabling js.

What you also can do is the following:

Masterpage has a inputfield and on submit it check the input value, if it's not empty it will save a cookie in the user it's browser.

On all the other pages just check for the cookie and when it does not exist redirect to the masterpage.

This can be made even secure by generating a unique cookie that's stored in a database for each user.

You can also do above with a session variable in asp that's set to true when a value has been submitted. Though this variable is reset when the browser is closed.

The method you choose depends on the website it's use case.

[+theblazingangel MVC]

Reiterating what others have been saying...

 

You must learn js in order to dynamically control what the user can do on your page like you describe.

 

You have at least the following two ways of implementing this in the page:

1. Assign an event handler to every link, button and form on the page, which simply cancels the navigation (by simply returning false if I remember correctly). JQuery will help you write some simple code to select all of the necessary HTML elements from your page and assign such an event handler. You would then have an event handler attached to this text box that then removes these event handlers to allow them to work again once your validation condition has been satisfied (textbox is not empty). It may also reapply them if the user deletes the textbox content leaving it empty or otherwise invalid. These event handlers may need to be created and assigned on page load.
2. Or, if your page structure allows it, while the textbox content is invalid, create a new "overlay" element which, with CSS, covers the entire page, and then with CSS place your text box on top of this. You may need an event handler on this overlay element to stop click events propagating down to things beneath it. This overlay can be added or removed to block or allow respectively user interaction with the rest of the page.

You would also need to add an event handler to block the user leaving the page via the back/forward browser navigation buttons, by closing the tab, by closing their browser, by clicking on a bookmark, by changing the url in the address bar, etc.

 

Understand that protection mechanisms like this are never perfect. A sufficiently knowledgeable/skilled user could remove such blocks with the web developer tools built into the browser for example.

 

You may want to seriously consider whether the design of your application could be improved. Your current requirement of such forced control over the users actions may be a result of a bad design. Why not describe to us in detail the functionality of your application and the problem you're trying to solve by implementing such restrictions. Perhaps we could dissect and discuss your design with you and then maybe come up with a better solution.

[SuperJediMedia]

I must use C# .NET, not JavaScript.

 

As for complexity, +theblazingangel I think you are thinking too complex, but I require nowhere as complex as blocking from going to another website, pressing back button, etc. Only that it can not goto another page linked in my site.

And, I don't even need a popup, just that it can not go to another page unless information has been entered.

 

ALL this should be really really easy to do, but I am just learning.

 

[Stoffel]

I haven't programmed in a long time but this seems like something you really want to handle on the client side

 

Can't you just have a general event handler for the click event?

In that event you can just check if the textbox is empty

If it is you let it go on with the link

if not you just do nothing

[SuperJediMedia]

I have realized that

Response.Redirect won't work inside Master Page.

 

I am still trying to figure out why my Info is null, but it treat as if it's not null?

[SuperJediMedia]

I got it!!

[Alwaysonacoffebreak]

Not be an ass or anything but the thing You're doing is the most annoying thing on webpages. It doesn't let You back out.

[Seahorsepip Veteran]

Just as I said before use asp session variables if you want to do it server side.

 

If you did something else then I'm interested in what exactly you did  :)

  On 16/11/2014 at 07:32, alwaysonacoffebreak said:

Not be an ass or anything but the thing You're doing is the most annoying thing on webpages. It doesn't let You back out.

Hmm he's just using the wrong words to explain what he wants, what he actually wants is just requiring a user to enter a field with something like a username before giving them access to the rest of the site.

[Alwaysonacoffebreak]

  On 16/11/2014 at 11:36, Seahorsepip said:

Just as I said before use asp session variables if you want to do it server side.

 

If you did something else then I'm interested in what exactly you did  :)

Hmm he's just using the wrong words to explain what he wants, what he actually wants is just requiring a user to enter a field with something like a username before giving them access to the rest of the site.

 

Oh okay. Then my bad. I just found it weird that he wanted to (by the title) to lock people down before they fill in a box. :D

[+theblazingangel MVC]

  On 16/11/2014 at 03:38, SuperJediMedia said:

I must use C# .NET, not JavaScript.

 

As for complexity, +theblazingangel I think you are thinking too complex, but I require nowhere as complex as blocking from going to another website, pressing back button, etc. Only that it can not goto another page linked in my site.

And, I don't even need a popup, just that it can not go to another page unless information has been entered.

 

ALL this should be really really easy to do, but I am just learning.

 

 

Why can you not use JavaScript? Is this arbitrary restriction imposed upon you because this is a homework exercise and your tutor has said so, or because you're "trying to learn how to program/design a website" and you don't yet understand how JavaScript fits in and how it may help you achieve what you're after, or because you know enough to recognise that the solution to your problem must be implemented in server side code but you haven't explained things well enough, or because JavaScript is/may-be disabled on the client browser which would cause problems??? Without any disrespect, you are just learning web-dev, whereas myself and others here have quite a lot of experience, so if we're suggesting that you use JavaScript for something and you tell us you can't, please provide an explanation as to why!

 

You've stated several times that you are trying to prevent the user from navigating to other pages on your site, but yet nowhere have you actually been clear enough about exactly what you're trying to achieve. Are you trying to just keep the user within this particular page you've been trying to build, with them having navigated to it somehow, until they have filled in this mysterious textbox (i.e. for some reason prevent them moving away to other pages, but they can load other pages say in a different tab without restriction), or are you trying to block access to all pages on the site until this mysterious textbox has been filled in (textbox displayed by all pages instead of proper content until filled in, or perhaps all pages redirect to the textbox page until it's filled in).

 

What you've described to us in every post so far is entirely ambiguous. It came across to me that you were trying to achieve the former of the two possibilities above, but you may well be trying to achieve the latter.

 

What I am trying to steer you towards is getting you to actually describe what this mysterious textbox is for, what data does it capture, and from there we could work towards figuring out which of these designs I've described above is the one you were trying to build and more importantly what problem exactly you are trying to solve. With a proper understanding of what problem you are trying to solve, we would then be in a position to not only guide you as to how to implement a solution, but also to assess whether your approach would actually work, and perhaps offer up a better one.